Are you implying that this patent should not have been granted?

I'm suggesting that the USPTO people can't spot glaring errors of logic in a simple introductory paragraph of text that is devoid of complicated technical or legal language.

No wonder they grant applications for obvious programming techniques, like oh ... the use of XOR to draw a sprite on a black-and-white pixel display, such that if it is drawn again at the same location, it is erased, restoring the original background.

You're taking this entirely too seriously. @marvin was very likely joking also.

Kazinator is making a fair point. But yes, I was making a joke ;)

I had to re-read that part. They are talking about an ordinary red or green laser pointer. The beam itself is hardly visible compared to the spot on the wall--unless your air contains a lot of dust or smoke or fog.

To anyone with a grade 5 science education, "visible light" means a frequency between IR and UV.

No beam of any type of light is visible in vacuum; it is superfluous to call it invisible in that sense because there is no contrasting opposite.

Patent office staff should have a decent background in science.